尝试在 python 中导入谷歌云库时出现“DefaultCredentialsError”

Question

I am attempting to import google-cloud and big-query libraries and running into default credentials error. I have attempted to set the credentials by downloading the json file from cloud portal and specifying the path to the file.

## Google Big Query
%reload_ext google.cloud.bigquery
from google.cloud import bigquery
bqclient = bigquery.Client(project = "dat-exp")
os.environ.setdefault("GCLOUD_PROJECT", "dat-exp")
os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = "path/xxxxx.json"



    ---------------------------------------------------------------------------
DefaultCredentialsError                   Traceback (most recent call last)
/tmp/ipykernel_2944/2163850103.py in <cell line: 81>()
     79 get_ipython().run_line_magic('reload_ext', 'google.cloud.bigquery')
     80 from google.cloud import bigquery
---> 81 bqclient = bigquery.Client(project = "dat-exp")
     82 os.environ.setdefault("GCLOUD_PROJECT", "dat-exp")


DefaultCredentialsError: Could not automatically determine credentials. Please set GOOGLE_APPLICATION_CREDENTIALS or explicitly create credentials and re-run the application. For more information, please see https://cloud.google.com/docs/authentication/getting-started

Answer 1

Default Credentials (ADC) is a method of searching for credentials.

Your code is setting the environment after the client has attempted to locate credentials. That means the client failed to locate credentials before you set up credentials. A quick solution is to move the line with bigquery.Client(...) to be after the os.environ(...) lines.

os.environ.setdefault("GCLOUD_PROJECT", "dat-exp")
os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = "path/xxxxx.json"
bqclient = bigquery.Client(project = "dat-exp")

I do not recommend the method that you are using (modify the environment inside the program). Either modify the environment before the program starts or specify the credentials to use when creating the client bigquery.Client() .

from google.cloud import bigquery
from google.oauth2 import service_account

key_path = "path/to/service_account.json"

credentials = service_account.Credentials.from_service_account_file(
    key_path, scopes=["https://www.googleapis.com/auth/cloud-platform"])

client = bigquery.Client(credentials=credentials, project='dat-exp')

Provide credentials for Application Default Credentials

However, the correct method of specifying credentials depends on where you are deploying your code. For example, applications can fetch credentials from the compute metadata service when deployed in Google Cloud.